The majority of human lung cancer occurs in the epithelium of the bronchus and is due to exposure to chemical carcinogens in tobacco smoke and in the environment. The main objective of the proposed research is to develop a cell culture system to study the process of neoplastic transformation in epithelial cells from human bronchus after treatment with the carcinogens; 4-nitroquinoline-1-oxide (4-NQO), benzo(a)pyrene (B(a)p) and crocidolite asbestos. Knowledge of the molecular events leading to neoplastic transformation of bronchial epithelial cells could result in the development of more effective methods to prevent and treat lung cancer. Bronchial epithelial cells will be isolated by dissociation techniques or grown from explants in primary cultures and identified by morphological (light and electron microscopy), cytochemical and immunological methods. Environmental conditions for serial propagation of the epithelial cells will be developed from quantitative studies of the effects of various media, hormones, growth factors, sera, substrates, etc., on growth in primary culture and in clonal culture. Well-characterized epithelial cell lines will be treated with various concentrations of either 4-N-QO, B(a)P or crocidolite asbestos. In some experiments, the epithelial cells will be treated with either 4-NQO or B(a)P in combination with crocidolite asbestos. Treated and control cells will be monitored for transformation by examining the cells for alterations in morphology, growth rate and karyotype, and the ability to grow in soft agar, elaborate certain lung-tumor associated antigens, and to produce tumors after transplantation into athymic, nude mice. These investigations should result in the development of normal, preneoplastic and neoplastic bronchial epithelial cell lines that will be used for further investigations of the molecular events leading to neoplastic transformation.